Tool and method of making same



M. G. KREAG Dec. 29, 1936.

Filed Sept. 15, 1932 INVENTOIR. MaZco/m 61117605- .1: H I TO EY Patented Dec. 29, 1936 UNITED STATES PATENT, OFFICE:

2,065,898 r001. AND METHOD or MAKING seam York Application September 15, 1932, Serial No. 633,232

17 Claims.

This invention relatesto implements or tools and to the method of making the same. The invention is more particularly applicable to the construction of such implements or tools as are used for impact drilling; digging or breaking up hard formations, such as rock drills, bucket teeth for'use in excavating, and gads for breaking up concrete and certain rock formations.

The invention will be herein illustrated and described more particularly in its application to gads although it is to be clearly understood that features of the invention are applicable to all manner of implements or tools wherein a durable cutting or drilling point or edge is desired.

Gads and other tools of the above character are ordinarily made of high carbon tool steel and are provided with a pointed end or sharp edge according to the nature of the tool. Before use, the sharp points or edges are tempered by quenching in water to increase their lasting qualities, and points so treated last in use any where from five minutes to five hours depending upon the nature of the formation to be broken up thereby and upon the degree of hardness to which the points have been tempered. It is highly desirable that a sharpenedpoint be dependable for use over a reasonably long period of time in order that too much of the winkmans time may not be consumed in tool dressing and in order that the cost of maintenance may not be disproportionate to the work accomplished with the tool. The quality of a tempering job,

is a matter of'hazard depending on the skill of the workman and upon other factorsbeyond his control. A high degree of skillis required if satisfactory results are to be obtained and an ordinary workman is seldom .sufllciently skilled to perform the'operation with any assurance of a reliable product; the operation being in fact, a blacksmiths job requiring shop facilities.

Gads are comparatively expensive tools, costing at the present market prices four or five dollars each, and, as heretofore constructed, wear out rapidly and require frequent and expensive 45 redressing and retempering to keep them sharp, besides consuming considerable time and energy and entailing other inconveniences to a workman operating therewith. In attempting to solve the above problems and 50' provide tools which willstand up under long use without necessity of redressing or repair, it has been proposed to cap the tip end or edge of tools with a layer of hard wear-resisting material, preferably welded thereto. Such a construction,

. 55 'while giving better results than a tempered tool,

is far from satisfactory inasmuch as the steel under the cap has a tendency to mushroom, forcing the cap to spall off before it has a chance to do any considerable amount of work. I have been able also to get quite good results with gads 5 by providing the tip of their pointed endsof durable wear-resisting material. A tool so ,tipped, while having wear-resisting qualities in the ratio of from three to five to one over those with tempered points, still leaves much to be desired in that it necessitates frequent Stelliting requiring considerable skill and therefore tending to discourage its use. No satisfactory substitute for the tempered tool heretofore used has to my knowledge been provided prior to my invention which lends itself to simple and inexpensive manufacture and maintenance operations that may be performed by a comparatively unskilled workman.

It is desirable, therefore, and an important object of this invention to provide an improved construction in implements and tools of the above character, which will stand up under long usage without redressing, resharpening or other maintenance operations; which will require little, or no skill in redressing and resharpening; which will have a long life and will not require frequent replacement; which will be largely selfsharpening; and will lend itself to a simple an inexpensive process of manufacture.

A further important object of the invention is to provide an improved and simple process of manufacture by which implements or tools of the above character and desirable qualities may be inexpensively manufactured without any considerable requirements of skill on the part of the manufacturer and without any special facilities for carrying out the process.

In the broad aspect of the invention, the implement or tool may comprise a supporting shank or body of strong, tough metal having its eflective working point or edge of a hard wear-resisting metallic substance projecting beyond the shank or body and bonded thereto, as by -welding.- Preferably this point or edge is a partof a core extending a considerable depth into the shank or body by which it is surrounded, and is supported on all sides by the body to which it is suitably bonded, as by being weldedthereto on all sides and throughout itsentire length except the protruding point or edge. The shank or body of the tool, while strong and tough, may be of soft, readily abra'dable metal so as to adapt the tool to be sharpened by grinding back the shank or body when the tool be- 55 comes dull. For convenience of manufacture, the shank or body may be provided with a longitudinally extending groove, in the bottom of which, the core is placed and this groove may be closed in behind the core in any suitable manner as by fillingthe same with a suitable material similar in its qualities to those of the shank or body.

A suitable process of manufacture, whereby implements or tools of the above character may be conveniently and inexpensively made, consists in providing a piece of suitable material, as high carbon tool steel, forming a recess or groove therein extending from one end or edge, as the case may be, back a considerable distance into the shank or body thereof and providing a core of hard wear-resisting metal in the recess or groove which is preferably welded to the bottom and sides thereof so as to form a bond between the core and supporting metal throughout the length of the core and, in the completed article, on all sides thereof. After bonding the core to the bottom and sides of the groove or recess, the latter may be closed behind the core as by filling in with material similar in quality to the body in molten state so as to completely encase the core; the filling material being preferably welded to the core and sides of the recess or groove, progressively, as it is deposited. The implement or tool may then be heat treated to refine the grain and remove crystalline structure so that the bond between the metal of the core and the supporting body may the better withstand shock and the shank or body may be shaped to a point or edge and sharpened so as to expose the core in a sharp point or edge as the case may be.

The above and other objects and novel features of the invention will become apparent from the following specifications taken with the accompanying drawing, in which Fig. 1 is a view in side elevation of a gad made in accordance with the present invention.

Fig. 2 is a fragmentary view on an enlarged scale compared with Fig. 1 showing a portion of the gad at its pointed end in longitudinal section. a i

Fig. 3 is a cross-sectional view on the same scale as Fig. 2, and on line 3--3, Fig. 1.

The invention is shown in the drawing as applied to a gad which may be used with rock drills or on the end of a bar or stafl. This tool comprises a shank I 0 which may be provided with the usual .collar ll formed integrally therewith. One end of the shank is drawn to' a point, as at l2, and the shank may be provided at this end with a recess or groove l3 extending from the tip end longitudinally of the shank rearwardly thereof a suitable distance, for example, about three or four inches with gads of standard construction. The side walls of the groove may diverge toward the outer side walls of the shank, as illustrated in Fig. 3.

The groove or recess is preferably of a depth sumciently greater than the radial dimension of the shank to position a core l4 placed in the bottom thereof coaxially of the shank although it may also, with good effect, be placed eccentric to said axis with certain types of tools. The core is desirably of a hard material more wear resisting than the supporting steel, as "Haynes Stellite", a non-ferrous alloy including as its principal ingredients tungsten, cobalt and chromium as described in the patents to Elwood Haynes Nos. 873,745; 1,057,423; 1,057,-

' aoeasos 828; and 1,150,113. The core is preferably welded to the bottom of the groove throughout its length and is supported on all sides by the metal of the shank, preferably of high carbon tool steel which is strong and tough while, at the same time, being sufficiently soft to be readily abradable in sharpening the tool and, under some conditions of work and, with certain types of tools to which the invention may be applied, being substantially self-sharpening. The groove or recess is closed back of the core in any suitable manner as by depositing a filler 15 of suitable material therein; the filler material preferably having qualities similar to those of the shank so as to provide substantially the same character of support and the same qualities as to abradability on all sides of the core. The filler, material is, therefore, desirably a tough ductile substance such as Hascrome, an alloy having iron, chromium, and manganese as its chief ingredients as set forth in the patent to Frederick M. Becket, 1,333,151, which is welded to the core l4 and to the shank Ill along the walls of the groove or recess. Hascrome lends itself admirably to the needs of the present situation since in addition to possessing the above desirable qualities of toughness and ductility it bonds readily both with the steel of the shank and the Stellite of the core. Other materials, however, as high carbon steel such as that of the shank may be used with excellent results.

In the manufacture of tools of this character I may take a bar of suitable metal, as high carbon tool steel and form a longitudinal recess or groove therein, such as the groove l3 referred to above, at one end. This'groove may be formed in any suitable manner as by milling or drop forging, either of which methods is simple and requires little skill on the part of the workman. The core may then be placed in the bottom of the groove and welded thereto throughout its length. To this end, the core may be preformed and placed in the groove as a unit but a preferable method is to deposit the core in place by a welding process in which the metal of the core is melted from a rod as in certain welding processes and is progressively bonded to the bottom of the groove as it is deposited, the groove being maintained the while at the point of deposit at welding temperature and in condition to bond with the metal of the core. The welding process-whereby metal is welded to a base by melting the former and flowing it onto the latter so as to bond therewith is herein referred to as weld-depositing.

A core of the desired thickness having been deposited and welded in place in this manner,

on the market in the form of welding bars and may be readily melted into the groove to fill the same.' This material as stated above bonds readily with other metals, both the steel of the shank and the-Stellite' of the core, and; is soft and ductile while being at the same time strong and'tough. It is desirable that the core have a welded bond on all sides and throughout its, length of contact with the shank and filler, so that it will be firmly supported against breakage by impact shock. To this end, the Hascrome is preferably welded to the core and to metallic substance for this purpose is -Hascrome referred to above, which is obtainable the sides of the groove by weldedepositing the same in the groove, and the'tool is afterwards heat treated in order to refine the grain of the steel. The cored end of the shank may then be ground to a point to expose theend of the core whereupon the tool is ready foruse. Thus, the tool may be provided with a pointed substantially conical end in which the major portion of the core is of substantially uniform cross section and is reinforced by the enclosing body portion of substantially uniform thickness on all sides of the core.

The end of .the tool may be resharpened when it becomes dull so long as there remains sufficient core in the shank; and a gad of standard dimensions having a core three or four inches long will. stand about twenty-five or thirty sharpenings. In sharpening the tool, it is only necessary to grind away the supporting material so as to expose the end of the core and to bring the core to a suitable point which is a. simple operation requiring little skill and may be performed at a trifling expense as compared with tempering. Under certain conditions, a tool made in accordance with the invention is substantially self-sharpening as in excavation bucket teeth and other situations where the tool digs into the hard surface it is intended to break up.

A gad in accordance with this invention will have a life equal to about five gads tempered according to previously known methods. These five gads would require a total of one hundred and. fifty expensive redressings in the course of their combined life as compared with the twenty-five or thirty resharpenings for the gad of my invention. My gad is therefore materially less expensive both as to initial cost and maintenance than a tempered gadbesides being more economical of the operator's timewhich is no iIICO i ISidCIabIG factor in the course of a piece of work being performed thereby.-

By the term weld-deposi "used hereinafter in the claims I mean the flowing of metal into the groove so as to form a welded. bond between the same and the surface of the groove.

I claim:

1. As an article of manufacture. an implement or tool for drilling or for breaking up hard formations by impact, the same ha g-an elongated body of tough abradable material; and an elongated core of a material of greater wearresistance than that of the said body, the core being disposed longitudinally of the body and completely encased by the body throughout at least the major portion of its length; said core having an end protruding from an end of the body, and the portion of the body adjacent the protruding end of the core being tapered on all sides along lines converging to a point.

2. An implement or tool for drilling or for breaking up hard formations by impact; 'coin-. prising a body of metallic material having a longitudinal groove; a metallic core in the bottom of the groove positioned coaxially with the a metallic core in the bottom of the groove positioned coaxially with the body; anda metallic filler of comparatively soft but tough metalli material in the grooveon top 'of the core.

4. An implement or' tool for use in drilling or breaking up hard formations by im t; comprising an elongated bodyof metallic material having a .longitudinal groove;- a metallic core in the bottom of the groove positioned along the longitudinal axis of the body and positioned entirely within the groove throughout at least the major portion of its length; said core being welded to the walls of the body at the groove substantially throughout the length of the core;

and a metallic material sealing the groove on top of the core.

5. An implement or tool for drilling or for breaking up hard formations by impact; comprising an elongated body of metallic material having a longitudinal groove; a layer of wearresisting metallic material welded to the bottom of the groove; and a flller of metal in the groove welded to the sides thereof and together with the body completely surrounding the core the layer of wear-resisting material being arranged coaxially with the body.

6. The method of making a'tool or implement which consists in forming a groove in a metallic body; weld-depositing -a core therein; and placing a filler in the groove weld-deposited to the sides of the groove; said core and bodybeing coaxially arranged.

7. The method of making a tool or imple-.

Y the cutting edge or point of the tool back into the body a substantial distance; welding a core therein soas to lie coaxially with the body andso as to weld, it to the sides and bottom 'of the groove; and closing the groove so as to encase the core on all sides.

. 9. A method of making an implement or tool having an axial core of wear-resistant metal and an elongated. body of strong metal relatively softer and less wear-resistant than said core and permanently secured to, enclosing, and

I uniformly reinforcing the major portion of said core, said method comprising forming a groove in the side of the body lengthwise of the longitudinal axis thereof and of such depth that said axis will'lie within said groove; inserting the core of wear-resistant metal in said groove, the core being at least as long as the groove and its longitudinal axis substantially coinciding with that of the body; and weld-depositing sumcient metal into and along said groove and onto said core to fill the groove and to permanently unite the body, the core, and the added metal.

10. The method of making an implement or tool of durable quality which consists in providing a bodypf metallic material; forming a groove longitudinally thereof and of a depth' greater than one-half of the dimension of the body perpendicular to its longitudinal axis; placing a metallic core' in the bottom of the groove so as to be coaxial with the body; and closing the groove 'by welding a metallic filler around the core.

11. The method of making an implement or tool of durable quality which. consists in pro- 75 tool of durable quality which consists in pro-' viding a rigid elongated body of metallic material; forming a groove longitudinally thereof and of a depth greater than one-half of the dimension 01' the body perpendicular to its longitudinal axis; placing a metallic core in the bottom of the groove; welding said core in the bottom 01 the groove; and closing the groove back of the core with metal weld deposited into the groove so as to be bound with the core and sides of the groove throughout the extent of the core.

13. The method of making an implement or tool of durablequality which consists in providing a rigid elongated body of metallic material; forming a groove longitudinally thereof and 01' a depth greater than onehalf of the dimension oi the body perpendicular to its longitudinal axis; welding a core in the bottom 01' the groove; closing the groove back oi the core by weld depositing metal into the groove so as to bond with the sides thereof and with the core throughout the entire extent oi. surfaces with which the weld deposited metal contacts; and heat treating the tool.

14. The method of making an implement adapted for drilling or breaking up hard formations, which comprises forming a longitudinal groove within an elongated body of at, least approximately uniform transverse cross-section formed of tough, readily-abradable metal, the said groove extending at least to the longitudinal axis of the body, weld-depositing a core of molten, hard, wear-resistant metal within the lower portion of the groove, thereafter filling the remainder of the groove above the said core with a molten body of relatively-soft, tough,

ductile metal, thereby welding the same to the core and to the first-named body along their respective surfaces of contact.

15. The method 01' making an implement adapted for drilling or breaking up hard formations, which comprises forming a longitudinal groove within an elongated body of at least approximately uniform transverse cross-section formed of tough, readily-abradable metal, the. said groove extending at least to the longitudinal axis of the body, weld-depositing a core of molten, hard, wear-resistant metal within the lower portion of the groove, thereafter filling the remainder of the groove above the said core with a molten body of relatively-soft, tough, ductile metal, thereby welding the same to the core and to the first-named body along their respective surfaces of contact, heat-treating the resultant composite structure, and tapering the latter at one end to form an implement having a point and to expose an end of the core.

16. An implement or tool comprising a body of tough, abradable, metallic material having a longitudinal groove; a core of metallic material of greater wear-resistance than that of said body weld-deposited into said groove and partly filling the same; and tough, abradable, metallic material on top oi said core secured within said groove and substantially completing the filling thereof.

17. An implement or tool having a pointed end and comprising a body of comparatively tough, abradable metal having a groove; a core of metal of greater wear-resistance than that of said body permanently secured within said groove, said body and core having coinciding longitudinal axes; a relatively thick filler 01 metal in said groove on top of said core and permanently secured to said body so that said core is uniformly supported on allsides over the major portion 0! its length; and an end oi said core projecting from an: end of said bodyand being pointed to constitute the pointed end of said implement, the exterior surface of said pointed end merging into the adjoming surface 01 said body.

MALCOLM G. KREAG. 

